1. Technical Field
The present disclosure relates to a relief valve and, more specifically, to a pressure relief valve with a singular body.
2. Discussion of the Related Art
A relief valve is a type of valve used to control an amount of fluid pressure in a system. When pressure in the system rises to a predetermined level, the relief valve will open to allow the pressurized fluid to flow from an auxiliary passage out of the system. By releasing the pressurized fluid when the predetermined pressure is reached or exceeded, the system may be protected against excessive pressure. Accordingly, relief valves may be used to ensure that system pressure does not exceed design limits.
A relief valve may include a spring bearing against a poppet. The spring provides a closing force on the poppet to maintain the valve in the closed position. Once the predetermined pressure level is achieved, the poppet is unseated and opens to create a passage through which the pressurized fluid can escape from the system. The unseating of the poppet compresses the spring. When the fluid pressure is sufficiently reduced, the spring pushes the poppet back into the closed position closing off the fluid's passage of escape.
FIG. 1 is a schematic diagram illustrating a conventional relief valve. The relief valve 10 may include a fluid inlet 11 within a body portion 12. Fluid in the inlet 11 presses against a poppet 13, which when in the closed position, may be at least partially within the body 12. The fluid presses against the poppet 13 with a pressure equal to the system pressure. A spring 14 provides a closing force against the poppet 13 such that the poppet 13 will remain in the closed position as long as the system pressure does not exceed the closing force of the spring 14. The spring 14 may push against a stationary shim 18. The poppet 13 is contained within a seat 15 and the seat 15 may allow the fluid to escape through an outlet 16 when the poppet 13 is in the open position. The spring 14 may be within a housing 17. The poppet 13 may at least partially enter the housing 17 when in an open position.
The body 12, the seat 15 and the housing 17 together form a body structure that confines the pressurized fluid. The seat 15 may be welded to both the body 12 and the housing 17 to confine the fluid. The welding may be performed using a brazing process. Alternatively, the seat 15 may be welded to the body 12 by an electron beam welding process and the seat 15 may be welded to the housing 17 by a laser tack welding process.
While modern welding techniques may be quite effective, the possibility still exists that leakage may occur at the welding points. This may be especially true for relief valves operating in high-pressure systems. Moreover, welding can add significantly to the complexity and cost of relief valve manufacture.